Multiscale cardiorespiratory complexity reveals autonomic signatures of Rajyoga meditation

Figures

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  Figure 1. Overview of the proposed experimental design and analysis pipeline. (A) Illustration of ECG electrode placement and recording setup. (B) Experimental design showing the three recording conditions: 10 min of pre-meditation, followed by 10 min of meditation and 10 min of post-meditation. In all three conditions, ECGs were recorded. (C) ECG feature extraction and analysis across the time domain, frequency domain, and non-linear domain measures. (D) Statistical analysis workflow.

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  Figure 2. Male linear HRV and respiration-frequency changes across the three physiological states. Boxplots of all subjects' trajectories are shown for representative linear indices in the male group across pre-meditation, during meditation, and post-meditation. (A) SDNN, (B) LF power, and (C) respiration frequency. SDNN, standard deviation of NN intervals; LF, low-frequency power.

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  Figure 3. Male non-linear HRV complexity changes across the three physiological states. Boxplots of all subjects' trajectories are shown for representative non-linear indices in the male group across pre-meditation, during meditation, and post-meditation. (A) SD2, (B) SampEn, and (C) Multiscale entropy(6). SD2, long axis Poincar descriptor; SampEn, sample entropy.

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  Figure 4. Female linear HRV and spectral changes across the three physiological states. Boxplots with participant wise trajectories are shown for representative linear and spectral indices in the female group across pre-meditation, during meditation, and post-meditation. (A) Mean RR (B) NN50 and (C) HF power. Mean RR, mean beat to beat interval; NN50, number of successive RR intervals differing by more than 50 ms; HF, high frequency power.

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  Figure 5. Female non-linear HRV complexity changes across the three physiological states. Boxplots with participant wise trajectories are shown for representative non-linear indices in the female group across pre meditation, during meditation, and post-meditation. (A) SD1 (B) correlation dimension D2 and (C) Multiscale entropy(10). SD1, short axis Poincar descriptor; D2, correlation dimension.

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  Figure 6. Male cardiorespiratory correlation matrices across the three physiological states. State-wise correlation matrices are shown for the male group. (A) Pre meditation, (B) during meditation, and (C) post-meditation. The displayed coefficients represent the associations among LF power, HF power, and respiration frequency within each state. LF, low frequency power; HF, high frequency power.

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  Figure 7. Female cardiorespiratory correlation matrices across the three physiological states. State-wise correlation matrices are shown for the female group. (A) Pre meditation, (B) during meditation, and (C) post-meditation. The displayed coefficients represent the associations among LF power, HF power, and respiration frequency within each state. LF, low frequency power; HF, high frequency power.